Rotary-type machine for stripping bark from round wood



A. F. L08

Nov. 5, 1968 ROTARY-TYPE MACHINE FOR STRIPPING BARK FROM ROUND WOOD Filed Feb. 28, 1966 United States Paten ABSTRACT OF THE DISCLOSURE I A rotary-type machine for removing bark from round wood having scraper-type bark strippers and cleaning members installed on a rotor mounted on a bed plate. The cleaning members are disposed downstream of the bark strippers relative to the direction of travel of the wood, the cleaning members having supporting surfaces which limit the depth of cut of the cutting edges thereof located downstream of the cutting edges.

This invention relates to devices used in the machine barking of round wood.

At present scraper-type rotary bar-kers are used for this purpose, but they prove ineffective in stripping iced wood since the inner bark and a portion of the bark proper remain untouched on the wood. Complete removal of bark and inner bark from the wood is required before treatment for pulp wood and clean-cut shapes.

These machines cannot remove all the bark from all kinds of wood, namely green wood, drift wood, fat wood or iced wood with a minimum loss of commercial wood.

Besides, these machines are frequently clogged by stripped bark and cannot provide for a reverse feed of wood in the process of debarking.

It is an object of this invention to eliminate the above disadvantages.

A more specific object of the invention is to provide a machine capable of stripping bark and inner bark from round wood, ice-covered wood inclusive, with a minimum loss of wood.

Another object of the invention is to provide for a reverse feed of wood into the machine when additional cleaning is necessary.

Still another object of the invention is to eliminate clogging of the machine by bark.

Said objects are attained by the provision of a rotarytype barking machine with scraper-type bark strippers after which in the travel of the wood in the process of debarking, are installed cutting members provided with supporting surfaces which prevent the cutting members from cutting deep into the wood, said supporting surfaces being installed behind the cutting edges.

The barking machine may also be made with the edges of the cutting members, e.g. drills, knives, or cutters, installed at an acute angle relative to the direction of the wood feed.

The machine may be made with the edges for selfopening of the working members (scraper strippers, bark cutting and cleaning knives) installed at an angle relative to the cross cut end of the fed wood on both sides of each working member.

For a better understanding of the invention, it will be illustrated by a description of an exemplary embodiment thereof with due reference to the accompanying drawings in which:

FIG. 1 shows the machine in partial section with bark cutting, bark stripping and bark cleaning knives;

FIG. 2 shows a cleaning knife taken in section along lines II;

FIG. 3 shows a bark cutting knife with variable depth of cut;

Ice

FIG. 4 shows a cutting knife taken in section along line IIIIIIofFIG. 3. K

The barking machine consists of a bedplate' with a'rotor on which are hinged working members including bark cutting knives 1, scraper-type bark strippers-2, and cleaning knives 3.'Said workingmembers are'pressed against the wood by centrifugal forces due to e the rotation of corresponding counterweights or by means er resilient members (springs, rubber rings, etc.). a

FIG. 1 shows the machine in which the' workingme'm bers are being pressed against the 'wood by the centrifugal forces of counterweights 4, -5 and 6."Springs 7, 8 and-9 are provided in the machine for opening the working members as the rotor stops.

Cleaning knives 3 are installed downstream, i.e. after the scraper-type bark strippers 2, relative to the direction of wood feed in the process of debarking.

The direction of wood feed in the machine is shown in FIG. 1 by arrow A. Supporting surfaces 10 of the cleaning knives 3 (FIG. 2) which limit the depth of out in the wood are installed after the cutting edges 11 at an acute angle a relative to the direction of the wood feed.

Edges 12 for self-opening of the working members 1, 2 and 3 are inclined towards the cross-cut end of the wood fed into the machine and are located on both sides of each bark stripper 2, cutting knife 1 and cleaning knife 3.

Bark cutting knife 1 (FIGS. 3 and 4) has a blade 13 which can be projected beyond the surfaces limiting the depth of cut to a variable extent depending on the thickness of the bark, which in its turn depends on the diameter of the wood to be debarked.

Thus, for instance, the height a of the blade 13 corresponds to the bark thickness of the wood of lesser diameter than height b which corresponds to a thicker bark in the wood of a greater diameter.

The position of surface 14 (FIGS. 3 and 4) limiting the depth of cut is selected so that when debarking wood of different diameters the cutting knife contacts the bark at different contact points which are spaced from each other. The cutting knife is secured to the rotor by means of an axle 15 of the hinge which is displaced from the line of contact of the blade and the bark.

In the machine, where the centrifugal force is employed for pressing the knives against the wood. to be debarked, the working members are opened as therotor is motionlessand are pulled to the center of rotation as the rotor is set in rotation.

The barking machine is operated as follows:

As the rotor drive is started the workingmembers 1, 2 and 3 of the barking machine are pulled together towards the center. The wood to be debarked is force-fed into the machine by its cross-cut end which presses against the edges for self-opening of the working members and opens them one after another. First the cutting knives 1 cut into the bark along a helix by corresponding sections of the blade. Then the cut bark is removed by the scraper strippers 2 and finally the remaining bark and the inner bark as well as other rough portions on the wood are cut off by the cleaning knives 3. The preliminarily cut bark is stripped off the wood as small rhomboids but not as long strips, which prevents the machine from clogging.

When cambium is to be removed, the cleaning knives are specially sharpened so that the depth of cut is as small as several tenths of a millimeter.

Dry and frozen wood is processed in two steps, first by the scraper strippers and then by by the cleaning knives 3.

When a repeated cleaning is required the wood can be fed back into the machine from the rear end by reversing over the feed direction mechanism. The opposite feed of material is made possible due to a special construction of the working members which are provided with opposite cutting edges inclined with respect to the cross-cut end of travel ofuthewood and thus can open the Working members both in direct and reverse feed of the wood.

The cleaning knives 3 are secured to the machine rotor so that they, can be removed in summer time when wood with damp bark is processed without removal of cambium,

What is claimed is:

1,; A rotary-type machine for removing bark from round wood comprising a bed plate; a rotor mounted on said bed plate; scraper-type bark strippers secured to said rotor; cleaningmembers installed on said rotor after said bark strippers relative to the direction of travel of the wood in the debarking process, said cleaning members having cutting edges and supporting surfaces limiting the depthlof cut of the cutting edges, said supporting surfaces being located after the cutting edges relative to the direcion of travel of the wood.

poring surfaces are positioned'at an acute angle-relativeto the direction of travel of the wood.

3. A machine as claimed in claim 1 wherein said strippers and cleaning members each have respective opposite cutting edges which are inclined relative to a plane normal to-the direction of traveLof the wood. I 1

1 References lited I UNITED STATESJPAT ENT S 2,623,558 12/1952 Andersson' l l44-208 2,860,672 11/1958 BrundelLet al 144208 3,221,785 11 /1965 ,Valo 144-208 GERALD A. DOST, Primary Examiner. 

